Process for preferentially extracting lithium from waste power battery

Abstract

The invention relates to the field of solid waste recovery, in particular to a process for preferentially extracting lithium from a waste power battery. The invention relates to a process for preferentially extracting lithium from a waste power battery. The process comprises the following steps: pretreating the battery, preparing a lithium ion adsorbent, leaching a lithium element, preparing a lithium ion extraction agent and extracting the lithium element. The lithium ion adsorbent is prepared in the lithium extraction process, and the lithium ion adsorbent has a stable skeleton structure, has a vacancy with high charge density in a narrow lattice gap, and can form a relatively strong electrostatic field, so that the lithium ion adsorbent has relatively good adsorption efficiency on lithium ions; the lithium ion extraction agent is also prepared, and hydrogen protons on cation carboxyl in the lithium ion extraction agent are easily dissociated in a solution, so that lithium ions are easily subjected to proton exchange with hydrogen ions, and the extraction effect is improved.

Description

Technical Field

[0001] The invention relates to the field of solid waste recycling, and in particular to a process for preferentially extracting lithium from waste power batteries. Background Art

[0002] With the rapid development of information technology and manufacturing industry, power batteries are everywhere in our daily life. As a component that can directly convert chemical energy into kinetic energy, power batteries do not produce noise, exhaust gas and other pollution during use. Due to their high energy density, they have been widely used as power sources for electric vehicles and electric vehicles. Lead-acid batteries, nickel-metal hydride batteries and lithium-ion batteries are the three most common types of battery applications. With the improvement of living standards, people have also put forward higher requirements for power output. Lithium-ion batteries have been rapidly and widely used due to their high energy density, long cycle life, low self-discharge rate, small size and light weight.

[0003] The lithium battery industry is booming, but the environmental pollution and resource waste it brings cannot be underestimated. Although the harm of ion battery components to the environment is less than that of lead-acid batteries and nickel-cadmium batteries, if the used lithium-ion batteries are not properly recycled, the shell may rupture in an extrusion or acid rain environment, and the organic solvents such as the electrolyte in them will endanger human health and pollute the soil, water and atmosphere. At the same time, traditional recycling technology focuses on cobalt and nickel separation, lacks lithium recovery, and has a low comprehensive metal recovery rate. Since there are still a large number of metals in lithium-ion batteries, among which lithium is the most important metal element, recycling lithium-ion batteries can not only realize the resource utilization of lithium metal, but also reduce the mining of lithium ore to a certain extent. However, the traditional lithium recovery efficiency is low, and the used extraction agent is not recycled, which increases the recovery cost.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a process for preferentially extracting lithium from waste power batteries.

[0006] A process for preferentially extracting lithium from waste power batteries, specifically comprising the following steps: S1: Battery pretreatment After the waste power battery is fully discharged, the battery shell is removed and the battery positive electrode sheet is disassembled to obtain the battery positive electrode sheet, and the battery positive electrode sheet is calcined, cooled, crushed, and sieved to obtain positive electrode active powder; S2: Preparation of lithium ion adsorbent KMnO 4The powder is added to distilled water and stirred, and then ethanol is added and heated to obtain basic manganese oxide, and then basic manganese oxide is added to lithium hydroxide solution and mixed evenly, and the product is ground, sintered, and added to HCl solution and stirred to obtain a lithium ion adsorbent; S3: Leaching lithium The positive electrode active powder is added to a sulfuric acid solution, and a reducing agent is added, and then the acid leaching liquid is filtered and diluted with filter paper. After the liquid becomes viscous, triethanolamine is added to form a homogeneous mixed liquid, and the homogeneous mixed liquid is placed in a hydrothermal reactor for reaction, and filtered to obtain a lithium-containing liquid; S4: Preparation of lithium ion extractant Adding an aqueous solution of 1-carboxymethyl-3-methylammonium-ammonium chloride into a reaction container, then adding an aqueous solution of lithium bis(trifluorosulfonyl)imide, stirring, standing and stratifying, removing the upper aqueous phase to obtain a transparent liquid crude product, washing with deionized water, then removing ethyl acetate by rotary evaporation, and finally vacuum drying to obtain a lithium ion extractant; S5: Extraction of lithium The lithium-containing liquid is mixed with a sulfuric acid solution, and the precipitate is filtered to obtain an extract consisting of an aqueous phase and an organic phase. A lithium ion adsorbent is then added thereto, stirred, and then a lithium ion extractant is added. The mixture is allowed to stand for phase separation, and the upper organic phase is separated for recovery. The lower aqueous phase is taken and centrifuged to obtain a high-purity lithium-containing solution. The separated organic phase is back-extracted with a sulfuric acid solution and then washed with deionized water to obtain a regenerated lithium ion extractant.

[0007] Furthermore, the pretreatment of the battery in step S1 specifically includes the following steps: S1.1: After the used power battery is fully discharged, the battery shell is removed and the battery positive electrode is obtained by disassembling; S1.2: Then put the positive electrode of the battery into an industrial constant temperature oven, set the heating rate to 20~25℃ / min, keep it at 200~400℃ for 100~120min, and finally cool it to room temperature and put it into a multi-functional crusher for crushing. The crushing time is 20~30s, and then use a 100~120 mesh sieve to sieve out the positive electrode active powder.

[0008] Furthermore, the step S2 of preparing the lithium ion adsorbent specifically includes the following steps: S2.1: 10-15 parts by mass of KMnO 4 The powder is added to 50-60 parts by weight of distilled water and stirred. After being completely dissolved, the powder is transferred to a hydrothermal reactor with a polytetrafluoroethylene liner, 5-8 parts by weight of ethanol is added, and after being stirred and mixed evenly, distilled water is continued to be added, the mixture is sealed, and the mixture is heated to 90-100° C. After reacting for 20-24 hours, the mixture is naturally cooled to room temperature, and then the reaction product is filtered, washed with ethanol and pure water, and dried in an oven to obtain basic manganese oxide; S2.2: Then, lithium hydroxide solution is added to the hydrothermal reactor, and basic manganese oxide is added and mixed evenly, and then the temperature of the hydrothermal reactor is raised to 120-130°C, and after reacting for 24-38 hours, the mixture is naturally cooled to room temperature; S2.3: The product in the hydrothermal reactor is filtered, then washed with ethanol and pure water, placed in an oven at 60-80°C for 2-4 hours, and then ground to 1-5 μm, and then placed in a muffle furnace at 400-500°C for sintering for 2-4 hours to obtain a spinel manganese lithium oxide solid. Finally, it is added to a 0.5-0.6 mol / L HCl solution and stirred for 5-6 hours to obtain a lithium ion adsorbent.

[0009] Furthermore, step S3 of leaching lithium element specifically comprises the following steps: S3.1: Take 10-20 parts by mass of positive electrode active powder and add it to a sulfuric acid solution with a concentration of 0.5-3 mol / L, adjust the reaction temperature to 80-90°C, add 4-5 parts by mass of 0.05-0.1 mol / L reducing agent under magnetic stirring, and the reaction time is 3.5-4 hours. After the reaction is completed, filter the acid leaching solution with 0.2-0.22 μm filter paper and dilute it 100-110 times; S3.2: After the liquid becomes viscous, add 4 to 6 parts by weight of triethanolamine and stir at room temperature for 30 to 40 minutes to form a homogeneous mixed liquid. Put the mixed liquid into a hydrothermal reactor with a polytetrafluoroethylene liner and react at 180 to 200°C for 1.5 to 2 hours. After the reaction is completed, cool to room temperature, filter and collect the filtrate to obtain a lithium-containing liquid.

[0010] Furthermore, the preparation of the lithium ion extractant in step S4 specifically comprises the following steps: S4.1: Add an aqueous solution of 1-carboxymethyl-3-methylammonium-ammonium chloride with a concentration of 2-3 mol / L into a reaction vessel, and then slowly add an equal amount of lithium bis(trifluorosulfonyl)imide aqueous solution, stir at room temperature, react for 4-6 hours, stand and separate, remove the upper aqueous phase to obtain a transparent liquid crude product; S4.2: The crude product obtained is further purified by ethyl acetate, washed with deionized water several times, and separated into layers until nitric acid-acidified AgNO is added dropwise to the aqueous layer. 3 After the solution is dissolved, no white precipitate is produced in the aqueous phase, and the ethyl acetate is removed by rotary evaporation to obtain a colorless or light yellow viscous liquid. Finally, the product is vacuum dried at 70-75°C for 12-14h to obtain a lithium ion extractant, which is stored under a nitrogen atmosphere.

[0011] Furthermore, the preparation of the lithium ion extractant in step S4 specifically comprises the following steps: S5.1: Mix the lithium-containing solution with 2~3 mol / L H 2 O2 and sulfuric acid solution at a volume ratio of 1: (1-1.2), filtering to remove the precipitate, obtaining an extract consisting of an aqueous phase and an organic phase, then adding 50-60% of the total volume of a lithium ion adsorbent to the extract, stirring at 80-85° C. for 30-40 minutes, then adding 50-60% of the total volume of a lithium ion extractant to the extract, standing to separate the phases, separating the upper organic phase for recycling, taking the lower aqueous phase into a centrifuge tube, centrifuging at a speed of 6000-6200 r / min for 10-20 minutes, and obtaining a high-purity lithium-containing solution; S5.2: The organic phase separated in step S5.1 is stripped with a sulfuric acid solution having a concentration of 1 to 1.5 mol / L to remove metal ions, and the volume ratio of the organic phase to the sulfuric acid solution is 1: (1 to 5). The organic phase is then washed with deionized water 2 to 3 times to remove the residual sulfuric acid in the organic phase, and a regenerated lithium ion extractant can be obtained.

[0012] Furthermore, the reducing agent in step S3.1 is NaHSO 3 .

[0013] The beneficial effects are: 1. A lithium ion adsorbent is prepared in the lithium extraction process of the present invention. The lithium ion adsorbent has a stable skeleton structure, and the size of the crystal vacancies left is just close to that of lithium ions, so it has good selectivity for lithium ions, and there are vacancies with high charge density in the narrow lattice gaps, which can form a strong electrostatic field, so it can have good adsorption efficiency.

[0014] 2. In the process of lithium extraction, the present invention prepares a lithium ion extractant with coordination effect. The hydrogen protons on the cationic carboxyl groups in the lithium ion extractant are easily dissociated in the solution, so that the lithium ions are easily exchanged with the hydrogen ions for protons, thereby improving the extraction effect. In addition, compared with traditional extractants, the lithium ion extractant has high extraction efficiency and mild extraction conditions. The extractant does not need to undergo saponification reaction and can be recycled, which effectively improves the recovery rate of lithium and reduces the cost of the extraction reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a process flow chart for preferentially extracting lithium from waste power batteries used in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Example 1: A process for preferentially extracting lithium from waste power batteries, such as Figure 1 As shown, the specific steps include: S1: Battery pretreatment S1.1: After the used power battery is fully discharged, the battery shell is removed and the battery positive electrode is obtained by disassembling; S1.2: Then put the positive electrode of the battery into an industrial constant temperature oven, set the heating rate to 20℃ / min, keep it at 200℃ for 100min, and finally cool it to room temperature and put it into a multi-functional crusher for crushing. The crushing time is 20s, and then use a 100-mesh screen to sieve out the positive electrode active powder.

[0018] S2: Preparation of lithium ion adsorbent S2.1: 10 parts by mass of KMnO 4 The powder was added to 50 parts by mass of distilled water and stirred. After being completely dissolved, the powder was transferred to a hydrothermal reactor with a polytetrafluoroethylene liner, 5 parts by mass of ethanol was added, and after being stirred and mixed evenly, distilled water was continued to be added, the mixture was sealed, and the mixture was heated to 90° C. After reacting for 20 hours, the mixture was naturally cooled to room temperature. The reaction product was then filtered, washed with ethanol and pure water, and dried in an oven to obtain basic manganese oxide. S2.2: Then, lithium hydroxide solution was added to the hydrothermal reactor, and basic manganese oxide was added and mixed evenly, and then the temperature of the hydrothermal reactor was raised to 120° C., and after reacting for 24 hours, the mixture was naturally cooled to room temperature; S2.3: The product in the hydrothermal reactor was filtered, then washed with ethanol and pure water, placed in an oven at 60°C for 2 hours, then ground to 1 μm, and then placed in a muffle furnace at 400°C for sintering for 2 hours to obtain a spinel manganese lithium oxide solid. Finally, it was added to a 0.5 mol / L HCl solution and stirred for 5 hours to obtain a lithium ion adsorbent.

[0019] S3: Leaching lithium S3.1: Take 10 parts by mass of the positive electrode active powder and add it to a 0.5 mol / L sulfuric acid solution. Adjust the reaction temperature to 80°C. Under magnetic stirring, add 4 parts by mass of 0.05 mol / L reducing agent NaHSO 3 , the reaction time is 3.5h. After the reaction is completed, the acid extract is filtered with 0.2μm filter paper and diluted 100 times; S3.2: After the liquid becomes viscous, add 4 parts by mass of triethanolamine and stir at room temperature for 30 minutes to form a homogeneous mixed liquid. The mixed liquid is placed in a hydrothermal reactor with a polytetrafluoroethylene liner and reacted at 180°C for 1.5 hours. After the reaction is completed, cool to room temperature, filter and collect the filtrate to obtain a lithium-containing liquid.

[0020] S4: Preparation of lithium ion extractant S4.1: Add a 2 mol / L 1-carboxymethyl-3-methylammonium-ammonium chloride aqueous solution into a reaction vessel, then slowly add an equal amount of bis(trifluorosulfonyl)imide lithium aqueous solution, stir at room temperature, react for 4 h, stand for stratification, remove the upper aqueous phase, and obtain a transparent liquid crude product; S4.2: The crude product obtained is further purified by ethyl acetate, washed with deionized water several times, and separated into layers until nitric acid-acidified AgNO is added dropwise to the aqueous layer. 3 After the solution is dissolved, no white precipitate is produced in the aqueous phase, and the ethyl acetate is removed by rotary evaporation to obtain a colorless or light yellow viscous liquid. Finally, the product is vacuum dried at 70°C for 12h to obtain a lithium ion extractant, which is stored under a nitrogen atmosphere.

[0021] S5: Extraction of lithium S5.1: Mix the lithium-containing solution with 2 mol / L H 2 O 2 and sulfuric acid solution at a volume ratio of 1:1, filtering to remove the precipitate, obtaining an extract consisting of an aqueous phase and an organic phase, then adding 50% of the total volume of a lithium ion adsorbent to the extract, stirring at 80° C. for 30 minutes, then adding 50% of the total volume of a lithium ion extractant to the extract, standing to separate the phases, separating the upper organic phase for recycling, taking the lower aqueous phase into a centrifuge tube, and centrifuging at a speed of 6000 r / min for 10 minutes to obtain a high-purity lithium-containing solution; S5.2: The organic phase separated in step S5.1 is stripped with a 1 mol / L sulfuric acid solution to remove metal ions, the volume ratio of the organic phase to the sulfuric acid solution is 1:1, and then washed twice with deionized water to remove the residual sulfuric acid in the organic phase, and the regenerated lithium ion extractant can be obtained.

[0022] Example 2: A process for preferentially extracting lithium from waste power batteries, such as Figure 1 As shown, the specific steps include: S1: Battery pretreatment S1.1: After the used power battery is fully discharged, the battery shell is removed and the battery positive electrode is obtained by disassembling; S1.2: Then put the positive electrode of the battery into an industrial constant temperature oven, set the heating rate to 20℃ / min, keep it at 200℃ for 100min, and finally cool it to room temperature and put it into a multi-functional crusher for crushing. The crushing time is 20s, and then use a 100-mesh screen to sieve out the positive electrode active powder.

[0023] S2: Preparation of lithium ion adsorbent S2.1: 15 parts by mass of KMnO 4The powder was added to 60 parts by mass of distilled water and stirred. After being completely dissolved, the powder was transferred to a hydrothermal reactor with a polytetrafluoroethylene liner, 8 parts by mass of ethanol was added, and after being stirred and mixed evenly, distilled water was continued to be added, the mixture was sealed, and the mixture was heated to 90° C. After reacting for 20 hours, the mixture was naturally cooled to room temperature. The reaction product was then filtered, washed with ethanol and pure water, and dried in an oven to obtain basic manganese oxide. S2.2: Then, lithium hydroxide solution was added to the hydrothermal reactor, and basic manganese oxide was added and mixed evenly, and then the temperature of the hydrothermal reactor was raised to 120° C., and after reacting for 24 hours, the mixture was naturally cooled to room temperature; S2.3: The product in the hydrothermal reactor was filtered, then washed with ethanol and pure water, dried in an oven at 60°C for 2 h, ground to 1 μm, and sintered in a muffle furnace at 400°C for 2 h to obtain a spinel manganese lithium oxide solid. Finally, it was added to a 0.6 mol / L HCl solution and stirred for 5 h to obtain a lithium ion adsorbent.

[0024] S3: Leaching lithium S3.1: 20 parts by mass of positive electrode active powder was added to a 0.5 mol / L sulfuric acid solution, the reaction temperature was adjusted to 80°C, and 5 parts by mass of 0.05 mol / L reducing agent NaHSO was added under magnetic stirring. 3 , the reaction time is 3.5h. After the reaction is completed, the acid extract is filtered with 0.2μm filter paper and diluted 100 times; S3.2: After the liquid becomes viscous, add 6 parts by mass of triethanolamine and stir at room temperature for 30 minutes to form a homogeneous mixed liquid. Put the mixed liquid into a hydrothermal reactor with a polytetrafluoroethylene liner and react at 180°C for 1.5 hours. After the reaction is completed, cool to room temperature, filter and collect the filtrate to obtain a lithium-containing liquid.

[0025] S4: Preparation of lithium ion extractant S4.1: Add a 3 mol / L aqueous solution of 1-carboxymethyl-3-methylammonium-ammonium chloride to a reaction vessel, then slowly add an equal amount of lithium bis(trifluorosulfonyl)imide aqueous solution, stir at room temperature, react for 4 h, stand for stratification, remove the upper aqueous phase, and obtain a transparent liquid crude product; S4.2: The crude product obtained is further purified by ethyl acetate, washed with deionized water several times, and separated into layers until nitric acid-acidified AgNO is added dropwise to the aqueous layer. 3 After the solution is dissolved, no white precipitate is produced in the aqueous phase, and the ethyl acetate is removed by rotary evaporation to obtain a colorless or light yellow viscous liquid. Finally, the product is vacuum dried at 70°C for 12h to obtain a lithium ion extractant, which is stored under a nitrogen atmosphere.

[0026] S5: Extraction of lithium S5.1: Mix the lithium-containing solution with 3 mol / L H 2 O 2 and sulfuric acid solution at a volume ratio of 1:1.2, filtering to remove the precipitate, obtaining an extract consisting of an aqueous phase and an organic phase, then adding 60% of the total volume of a lithium ion adsorbent to the extract, stirring at 80°C for 30 minutes, then adding 60% of the total volume of a lithium ion extractant to the extract, standing to separate the phases, separating the upper organic phase for recycling, taking the lower aqueous phase into a centrifuge tube, and centrifuging at a speed of 6000 r / min for 10 minutes to obtain a high-purity lithium-containing solution; S5.2: The organic phase separated in step S5.1 is stripped with a 1 mol / L sulfuric acid solution to remove metal ions, the volume ratio of the organic phase to the sulfuric acid solution is 1:5, and then washed twice with deionized water to remove the residual sulfuric acid in the organic phase to obtain a regenerated lithium ion extractant.

[0027] Example 3: A process for preferentially extracting lithium from waste power batteries, such as Figure 1 As shown, the specific steps include: S1: Battery pretreatment S1.1: After the used power battery is fully discharged, the battery shell is removed and the battery positive electrode is obtained by disassembling; S1.2: Then put the positive electrode of the battery into an industrial constant temperature oven, set the heating rate to 25℃ / min, keep it at 400℃ for 120min, and finally cool it to room temperature and put it into a multi-functional crusher for crushing. The crushing time is 30s, and then use a 120-mesh screen to sieve out the positive electrode active powder.

[0028] S2: Preparation of lithium ion adsorbent S2.1: 10 parts by mass of KMnO 4 The powder was added to 50 parts by mass of distilled water and stirred. After being completely dissolved, the powder was transferred to a hydrothermal reactor with a polytetrafluoroethylene liner, 5 parts by mass of ethanol was added, and after being stirred and mixed evenly, distilled water was continued to be added, the mixture was sealed, and the mixture was heated to 100° C. After reacting for 24 hours, the mixture was naturally cooled to room temperature. The reaction product was then filtered, washed with ethanol and pure water, and dried in an oven to obtain basic manganese oxide. S2.2: Then, lithium hydroxide solution was added to the hydrothermal reactor, and basic manganese oxide was added and mixed evenly, and then the temperature of the hydrothermal reactor was raised to 130° C., and after reacting for 38 hours, the reactor was naturally cooled to room temperature; S2.3: The product in the hydrothermal reactor was filtered, then washed with ethanol and pure water, dried in an oven at 80°C for 4 hours, ground to 5 μm, and sintered in a muffle furnace at 500°C for 4 hours to obtain a spinel manganese lithium oxide solid. Finally, it was added to a 0.6 mol / L HCl solution and stirred for 6 hours to obtain a lithium ion adsorbent.

[0029] S3: Leaching lithium S3.1: Take 10 parts by mass of the positive electrode active powder and add it to a 0.5 mol / L sulfuric acid solution. Adjust the reaction temperature to 90°C. Under magnetic stirring, add 4 parts by mass of 0.05 mol / L reducing agent NaHSO 3 , the reaction time is 4h. After the reaction is completed, the acid extract is filtered with 0.22μm filter paper and diluted 110 times; S3.2: After the liquid becomes viscous, add 4 parts by mass of triethanolamine and stir for 30 minutes at room temperature to form a homogeneous mixed liquid. The mixed liquid is placed in a hydrothermal reactor with a polytetrafluoroethylene liner and reacted at 200°C for 2 hours. After the reaction is completed, cool to room temperature, filter and collect the filtrate to obtain a lithium-containing liquid.

[0030] S4: Preparation of lithium ion extractant S4.1: Add a 2 mol / L 1-carboxymethyl-3-methylammonium-ammonium chloride aqueous solution into a reaction vessel, then slowly add an equal amount of bis(trifluorosulfonyl)imide lithium aqueous solution, stir at room temperature, react for 6 h, stand for stratification, remove the upper aqueous phase to obtain a transparent liquid crude product; S4.2: The crude product obtained is further purified by ethyl acetate, washed with deionized water several times, and separated into layers until nitric acid-acidified AgNO is added dropwise to the aqueous layer. 3 After the solution is dissolved, no white precipitate is produced in the aqueous phase, and the ethyl acetate is removed by rotary evaporation to obtain a colorless or light yellow viscous liquid. Finally, the product is vacuum dried at 75°C for 14h to obtain a lithium ion extractant, which is stored under a nitrogen atmosphere.

[0031] S5: Extraction of lithium S5.1: Mix the lithium-containing solution with 2 mol / L H 2 O 2 and sulfuric acid solution at a volume ratio of 1:1.2, filtering to remove the precipitate, obtaining an extract consisting of an aqueous phase and an organic phase, then adding 50% of the total volume of a lithium ion adsorbent to the extract, stirring at 85°C for 40 minutes, then adding 50% of the total volume of a lithium ion extractant to the extract, standing for phase separation, separating the upper organic phase for recycling, taking the lower aqueous phase into a centrifuge tube, and centrifuging at a speed of 6200 r / min for 20 minutes to obtain a high-purity lithium-containing solution; S5.2: The organic phase separated in step S5.1 is stripped with a 1.5 mol / L sulfuric acid solution to remove metal ions, the volume ratio of the organic phase to the sulfuric acid solution is 1:1, and then washed with deionized water three times to remove the residual sulfuric acid in the organic phase, and the regenerated lithium ion extractant can be obtained.

[0032] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A process for preferentially extracting lithium from waste power batteries, characterized in that: The specific steps include: S1: Battery pretreatment After the waste power battery is fully discharged, the battery shell is removed and the battery positive electrode sheet is disassembled to obtain the battery positive electrode sheet, and the battery positive electrode sheet is calcined, cooled, crushed, and sieved to obtain positive electrode active powder; S2: Preparation of lithium ion adsorbent The KMnO4 powder is added to distilled water and stirred, and then ethanol is added and heated to obtain basic manganese oxide, and then basic manganese oxide is added to lithium hydroxide solution and mixed evenly, and the product is ground, sintered, and added to HCl solution and stirred to obtain a lithium ion adsorbent; S3: Leaching lithium The positive electrode active powder is added to a sulfuric acid solution, and a reducing agent is added, and then the acid leaching liquid is filtered and diluted with filter paper. After the liquid becomes viscous, triethanolamine is added to form a homogeneous mixed liquid, and the homogeneous mixed liquid is placed in a hydrothermal reactor for reaction, and filtered to obtain a lithium-containing liquid; S4: Preparation of lithium ion extractant Adding an aqueous solution of 1-carboxymethyl-3-methylammonium-ammonium chloride into a reaction container, then adding an aqueous solution of lithium bis(trifluorosulfonyl)imide, stirring, standing and stratifying, removing the upper aqueous phase to obtain a transparent liquid crude product, washing with deionized water, then removing ethyl acetate by rotary evaporation, and finally vacuum drying to obtain a lithium ion extractant; S5: Extraction of lithium The lithium-containing liquid is mixed with a sulfuric acid solution, and the precipitate is filtered to obtain an extract consisting of an aqueous phase and an organic phase. A lithium ion adsorbent is then added thereto, stirred, and then a lithium ion extractant is added. The mixture is allowed to stand for phase separation, and the upper organic phase is separated for recovery. The lower aqueous phase is taken and centrifuged to obtain a high-purity lithium-containing solution. The separated organic phase is back-extracted with a sulfuric acid solution and then washed with deionized water to obtain a regenerated lithium ion extractant.

2. A process for preferentially extracting lithium from waste power batteries according to claim 1, characterized in that: Step S1: The pretreatment of the battery specifically includes the following steps: S1.1: After the used power battery is fully discharged, the battery shell is removed and the battery positive electrode is obtained by disassembling; S1.2: Then put the positive electrode of the battery into an industrial constant temperature oven, set the heating rate to 20~25℃ / min, keep it at 200~400℃ for 100~120min, and finally cool it to room temperature and put it into a multi-functional crusher for crushing. The crushing time is 20~30s, and then use a 100~120 mesh sieve to sieve out the positive electrode active powder.

3. A process for preferentially extracting lithium from waste power batteries according to claim 1, characterized in that: Step S2: The preparation step of the lithium ion adsorbent specifically comprises the following steps: S2.1: Add 10-15 parts by mass of KMnO4 powder to 50-60 parts by mass of distilled water and stir. After it is completely dissolved, transfer it to a hydrothermal reactor with a polytetrafluoroethylene liner, add 5-8 parts by mass of ethanol, stir and mix evenly, continue to add distilled water, seal, heat to 90-100°C, react for 20-24 hours, cool naturally to room temperature, then filter the reaction product, wash it with ethanol and pure water, and put it in an oven to dry to obtain basic manganese oxide; S2.2: Then, lithium hydroxide solution is added to the hydrothermal reactor, and basic manganese oxide is added and mixed evenly, and then the temperature of the hydrothermal reactor is raised to 120-130°C, and after reacting for 24-38 hours, the mixture is naturally cooled to room temperature; S2.3: The product in the hydrothermal reactor is filtered, then washed with ethanol and pure water, placed in an oven at 60-80°C for 2-4 hours, and then ground to 1-5 μm, and then placed in a muffle furnace at 400-500°C for sintering for 2-4 hours to obtain a spinel manganese lithium oxide solid. Finally, it is added to a 0.5-0.6 mol / L HCl solution and stirred for 5-6 hours to obtain a lithium ion adsorbent.

4. A process for preferentially extracting lithium from waste power batteries according to claim 3, characterized in that: Step S3 of leaching lithium element specifically comprises the following steps: S3.1: Take 10-20 parts by mass of positive electrode active powder and add it to a sulfuric acid solution with a concentration of 0.5-3 mol / L, adjust the reaction temperature to 80-90°C, add 4-5 parts by mass of 0.05-0.1 mol / L reducing agent under magnetic stirring, and the reaction time is 3.5-4 hours. After the reaction is completed, filter the acid leaching solution with 0.2-0.22 μm filter paper and dilute it 100-110 times; S3.2: After the liquid becomes viscous, add 4 to 6 parts by weight of triethanolamine and stir at room temperature for 30 to 40 minutes to form a homogeneous mixed liquid. Put the mixed liquid into a hydrothermal reactor with a polytetrafluoroethylene liner and react at 180 to 200°C for 1.5 to 2 hours. After the reaction is completed, cool to room temperature, filter and collect the filtrate to obtain a lithium-containing liquid.

5. A process for preferentially extracting lithium from waste power batteries according to claim 1, characterized in that: Step S4: Preparation of lithium ion extractant specifically comprises the following steps: S4.1: Add an aqueous solution of 1-carboxymethyl-3-methylammonium-ammonium chloride with a concentration of 2-3 mol / L into a reaction vessel, and then slowly add an equal amount of lithium bis(trifluorosulfonyl)imide aqueous solution, stir at room temperature, react for 4-6 hours, stand and separate, remove the upper aqueous phase to obtain a transparent liquid crude product; S4.2: The crude product obtained is further purified by ethyl acetate, washed with deionized water for several times, and separated into layers until no white precipitate is produced in the aqueous layer after the AgNO3 solution acidified with nitric acid is added dropwise to the aqueous layer. The ethyl acetate is then removed by rotary evaporation to obtain a colorless or light yellow viscous liquid. Finally, the product is vacuum dried at 70-75°C for 12-14h to obtain a lithium ion extractant, which is then stored under a nitrogen atmosphere.

6. A process for preferentially extracting lithium from waste power batteries according to claim 5, characterized in that: Step S4: Preparation of lithium ion extractant specifically comprises the following steps: S5.1: Mix the lithium-containing solution with a solution containing 2-3 mol / L H2O2 and sulfuric acid in a volume ratio of 1: (1-1.2), filter to remove the precipitate, and obtain an extract consisting of an aqueous phase and an organic phase, then add 50-60% of the total volume of the system lithium ion adsorbent thereto, stir at 80-85°C for 30-40 min, then add 50-60% of the total volume of the system lithium ion extractant, let stand for phase separation, separate the upper organic phase for recovery, take the lower aqueous phase into a centrifuge tube, centrifuge at 6000-6200 r / min for 10-20 min, and obtain a high-purity lithium-containing solution; S5.2: The organic phase separated in step S5.1 is stripped with a sulfuric acid solution having a concentration of 1 to 1.5 mol / L to remove metal ions, and the volume ratio of the organic phase to the sulfuric acid solution is 1: (1 to 5). The organic phase is then washed with deionized water 2 to 3 times to remove the residual sulfuric acid in the organic phase, and a regenerated lithium ion extractant can be obtained.

7. A process for preferentially extracting lithium from waste power batteries according to claim 4, characterized in that: The reducing agent in step S3.1 is NaHSO3.

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